Anode structure for electron discharge devices



Sept- 30, 1952 P. 1.. SPENCER 2,612,623

ANODE STRUCTURE FOR ELECTRON DISCHARGE DEVICES Filed Oct. 26, 1949 INLET1 OUTLET FIG. 2 22 INVENTOIZ PERCY L. SPENCER BY M Patented Sept. 30,1952 ODE "STRUCTURE ,FOR "EL DISCHARGE DEVICES :Percy.L ..Spencer, WestNewton,1Mass., assignor-to Raytheon. =Manufacturing Company,

Newton,

Y .Mass., aeorporation of Delaware Application October 26, 194SSerialNo.123j64'1 This invention relates to electron ..dischargedevices,r-especially, buttnot necessarily, zlof the -magnetron type, andmore particularly to the cano'des of such'devices.

":In'highpower devices of thegeneral fchar- -acter indicated, especiallythose designed for the :generation of microwave energy: it 3 ism-usually:necessary, in the interest of heat dissipation, either to build theanode of excessively-large size, or provide the same with complicatedcooling arrangements. It isto 'the elimination of these disadvantagesthat the present invention is pri- :marily. :addressed. I i

It is among the objects of :tbezpresent inVention toprovidean-anodeiorlan ;electron discharge device which is simple inconstruction,

yetcapable of high heat dissip'ation.

lit -"is a'further object of the present invention itoprovide-an anode,havingthe foregoing desirable characteristics, which is inexpensive tofabricate and assemble andwhi'ch is of'reasonable'size. f

I "These and other objects dfthef present inven- %tion, which willbecome more-fapparent asthe detailed "description thereof progresses,"are attained, broadly, in the following manner.

The invention contemplates the provision of a hollow tubular memberwhich is alternately bent in opposite directions to provide anode armsseparated by 1 cavity resonators. Preferably, I

after so bending the hollow member, it is formed into a circle andmounted in a cylindrical body which may then be hermetically sealed. Theresulting radially disposed anode arms define a central space in which acathode may be mounted, and, when such a structure is provided with asuitable potential difference between the cathode and the anode, and anappropriate axial magnetic field is applied parallel to the cathode,microwave energy may be generated of a frequency primarily depending, ina manner well known to those skilled in the art, on the geometry of thecavity resonators intermediate the anode arms. The ends of the tubularmember, between which there is a continuous passage, are brought out ofthe envelope, one end functioning as an inlet for a coolant, such aswater, and the other end functionin as an outlet for such coolant. Bymaintaining a constant coolant flow, the anode is maintained at asuitably low temperature and an eflicient high power microwave generatorof reasonable size results.

In the accompanying specification there shall be described, and in theannexed drawing shown,

iclaim. (01.:315-40) "aani illustrative tembodiment of 1' theanode-structure of the present invention. It is, .howeveni to 1 isnot-to'be 'shown an'd described for purposes-of illustration "only;inasmuch as changes therein may be made 'without the exercise ofinvention andwithin thettrue spirit'and scope of the claim hereto apended.

be clearly understood. that the present invention limited' tothe exactdetails-herein In said drawing: Fig. 1 is'a longitudinal sectional viewof an electron "discharge device including an anode made in accordancewith the present invention;

and

Fig. '2 is 1 a transverse" sectional view 1 taken along'line 2 -2 ofFig; l.

"Referring now more in detail "to the aforesaid'illustrative'embo'diment of the presentin- *vent'ioh, with 'particularreference to the drawing "illustratingthe' same, the numeral [0 '"gen-*erally designates anelectron discharge deviceof themagnetron type.'Such a tube comprises,

broadly, a. cathode structure I-l, an anode struc- "ture l2 spacedfrom-and surrounding said cath- "odestructure, and means 13 forestablishinga "magnetic field in the interelectrode space, ina

direction transverse to the electron path between the cathode and theanode structures.

While not limited thereto, the cathode structure ll may comprise acathode sleeve l4 pro-' vided with any preferred electron-emissivecoating 15, said sleeve being carried by a tubular member IS, the outerend of which carries another tubular member I'I. Mounted within thesleeve I4 is a cathode heater l8, one end of said heater beingelectrically connected, as at 19, to said sleeve, and the other endbeing con-, nected to a lead-in conductor 20 which passes downwardlythrough the tubular members I 6 and I1, insulated therefrom by beads 2|and 22. The tubular member l6 carries, adjacent the outer end thereof, aheat-radiating structure 23.

The entire cathode structure H is supported from the anode structure I2by securing the tubular member IE to a ferrule 24 which depends from aninsulating sleeve 25, in turn, depending from a tubular member 26. Thelatter is carried in a recess formed in a pole piece 21 secured to theanode structure l2, said pole piece being provided with a central borethrough other pole piece 28, and an external magnet not shown,constitute the means l3 for establishat points opposite the Fig. 2,being alternately bent in opposite directions to provide electronreceiving anode arms 33 separated by cavity resonators 34. The member 32is, after formation of the anode arms and intervening cavity resonators,formed into a circle whereby the anode arms become radially disposed,with the inner ends thereof defining a cathode space 35. The cavityresonators open at one end into the space 35, and the member 32 may befixed into the cylindrical body by brazing closed ends of said cavityresonators. f

The outer'ends of the hollow member 32 communicate with the exterior ofthe anode structure l2.and may be connectedto provide, respectively, aninlet and outletfor a coolant, such as water, which, in circulatingthrough the continuous passageibetween the inlet and outlet ends -of themember 32, maintain the anode structureat :a reasonably low temperature.I

. The'device is completed by a conventional-output loop 36 extendinginto theanode structure l2;and disposed adjacent the upper or lower'edgeof one of the anode arms 33.

When the cathode sleeve [4 is heated to thermionic emission, asby asource opvoltage 31, .and the anode structureis maintained at a suitablepositive potentialgwith respect to the cathode, as by a sourceofvoltage3 8, the device described oscillates to generate microwave energy of afrequency depending, primarily onthc physical structure of the cavityresonators incorporated in the anode structure.

This completes. the description of the aforesaid illustrative embodimentof the'present invention. It will be noted from all of the fore- 4 goingthat the present invention provides an anode for an electron dischargedevice which is simple in construction, easy and economical to fabricateand assemble, may be made of a reasonable size, and is highly efiicientin dissipating the large quantities of heat generated in a microwavegenerator designed for delivering energy at high power levels.

Other objects and advantages of the device of the present invention willreadily occur to those skilled in the art to which the same relates.

What is claimed is: A magnetron comprising: a hermetically sealedcylindrical envelope; a cathode centrally disposed in said envelope; andan anode spaced from and surrounding said cathode; said anode includinga hollow flattened tubular member successively bent in oppositedirections to provide alternate arms facing said cathode and interveningarms secured to said envelope; each adjacent pair of the arms facingsaid cathode,together with the arm therebetween secured to saidenvelope, defining a cavity resonator of appreciable dimension in thedirection of said cathode; said hollow tubular member providing acontinuous, passage between the ends thereof, andsaid endscommunicatingwith th exterior of said envelope and constituting, respectively, fluidinlet. .and

outlet ports. y

, 1 PERCY L. SPENCER...

REFERENCES CITED I The following references are of recordinthe file ofthis patenti 1 UNITED STATES PATENTS 7 Number Name 1 Date 1,459,417Schwerin June 19, 1923 1,830,802 McCullough Nov. 10,; 1931 2,428,193Blewett Sept. 30, 1947 2,451,987 Sloan Oct.;19,;1948 2,474,898 HeisingJuly 5, 1949 2,497,831 De Vore Feb. 14, 1950 2,546,773 Nelson Mar. 27,1951 2,548,808

Nichols Apr. 10, 1951

